"Cross-posting" means addressing a message to more than one
newsgroup at once. Just as you can send an E-mail message to more
than one recipient, you can send a newsgroup message to more than
one newsgroup.
I see that you're using Outlook Express. When you start a
message, click on the word "Newsgroups" in the message header.
You can add other newsgroups there. Or you can type their names,
separated by semi-colons, in the box.
When you crosspost, instead of doing it way you did, all the
responses stay together. So, assuming you crosspost to newsgroups
A and B, if Mr. X replies to your message in newsgroup A, Mr. Y,
who reads newsgroup B but not A, sees Y's response and can reply
to it.
Be careful, though. Crossposting is widely frowned upon in
newsgroups, mostly because spammers use this technique to easily
send spam all over the place. But crossposting isn't necessarily
bad, if you use it only for a few related newsgroups.
Crossposting is bad when you use it to send messages all over the
place to groups which have nothing to do with each other.
